系列文章目录

MNN createFromBuffer（一）
MNN createRuntime（二）
MNN createSession 之 Schedule（三）
MNN createSession 之创建流水线后端（四）
MNN Session::resize 之流水线编码（五）
MNN Session 创建执行器（六）

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1、createSession

    依据 ScheduleConfig 和 RuntimeInfo 创建会话。

// source/core/Interpreter.cpp
Session* Interpreter::createSession(const ScheduleConfig& config, const RuntimeInfo& runtime) {return createMultiPathSession({config}, runtime);
}

1.1 createMultiPathSession

// source/core/Interpreter.cpp
Session* Interpreter::createMultiPathSession(const std::vector<ScheduleConfig>& configs, const RuntimeInfo& runtime) {// ...auto result = newSession.get();auto validForResize = info.validForResize;if (validForResize && mNet->modes.inputMode == Session_Input_Inside && mNet->modes.resizeMode == Session_Resize_Direct) {result->resize();}if ((!mNet->cacheFile.empty()) && (!valid) && mNet->modes.backendMode == Session_Backend_Fix) {// Try to save extra cacheauto buffer = result->getCache();if (buffer.first != nullptr && buffer.second > 0) {MNN_PRINT("Write cache to %s, size = %zu\n", mNet->cacheFile.c_str(), buffer.second);writeCacheFile(mNet, buffer);mNet->lastCacheSize = buffer.second;// Write CachecacheMode = cacheMode | 2;}}// Reset cacheresult->loadCache(nullptr, 0);mNet->sessions.emplace_back(std::move(newSession));#ifdef MNN_INTERNAL_ENABLEDint precision = BackendConfig::Precision_Normal;if (nullptr != configs[0].backendConfig) {precision = configs[0].backendConfig->precision;}int mode = configs[0].mode;mNet->sessionInfo.insert(std::make_pair(result, std::make_tuple(precision, mode)));if (shouldLog(FREQ_HIGH)) {std::map<std::string, std::string> metrics = mNet->basicLogginData;metrics.emplace("UUID", mNet->uuid);metrics.emplace("Time", std::to_string((float)_timer.durationInUs() / 1024.0f));metrics.emplace("Backend", std::to_string(configs[0].type));metrics.emplace("Precision", std::to_string(precision));metrics.emplace("Mode", std::to_string(mode));metrics.emplace("Cache", std::to_string(cacheMode));metrics.emplace("CacheSize", std::to_string((float)(mNet->lastCacheSize / 1024.0f)));metrics.emplace("ModelSize", std::to_string ((float)mNet->buffer.size() / 1024.0f / 1024.0f));metrics.emplace("Usage", std::to_string((int) mNet->net->usage()));metrics.emplace("API", "Interpreter::createMultiPathSession");logAsync(metrics);}
#endif // MNN_INTERNAL_ENABLEDreturn result;
}

1.1.1 Session::resize

// source/core/Session.cpp
ErrorCode Session::resize() {// ...if (mNeedMalloc) {// Set needResize = true for easy for judge in runSession when errormNeedResize = true;// Turn Pipeline to Command Buffer and Malloc resource// TODO: Separate Schedule and Mallocbool forbidReplace = permitCodegen;if (mInfo.constReplaceBackend != nullptr) {forbidReplace = true;}for (auto& iter : mPipelines) {auto error = iter->allocMemory(firstMalloc, forbidReplace);if (NO_ERROR != error) {return error;}}if(mMemoryUsageMode == Interpreter::Session_Memory_Collect) {#ifdef LOG_VERBOSEfloat memory = 0.0f;#endiffor (auto& iter : mRuntime.first) {iter.second->onGabageCollect(0);#ifdef LOG_VERBOSEmemory += iter.second->onGetMemoryInMB();#endif}#ifdef LOG_VERBOSEFUNC_PRINT_ALL(memory, f);#endif}mNeedMalloc = false;mNeedResize = false;}#ifdef LOG_VERBOSEMNN_PRINT("session after resize\n");for (auto& iter : mOutputs) {auto& outputTensor = iter.second;MNN_PRINT("output name:%s, ptr:%p,shape:", iter.first.c_str(), outputTensor);outputTensor->printShape();MNN_PRINT("\n");}
#endifreturn NO_ERROR;
}